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121.
122.
Nitrogen enrichment in runoff sediments as affected by soil texture in Beijing mountain area 总被引:3,自引:0,他引:3
Yang Yang Zhihan Ye Baoyuan Liu Xianqin Zeng Suhua Fu Bingjun Lu 《Environmental monitoring and assessment》2014,186(2):971-978
Enrichment ratio (ER) is widely used in nonpoint source pollution models to estimate the nutrient loss associated with soil erosion. The objective of this study was to determine the ER of total nitrogen (ERN) in the sediments eroded from the typical soils with varying soil textures in Beijing mountain area. Each of the four soils was packed into a 40 by 30 by 15 cm soil pan and received 40-min simulated rainfalls at the intensity of 90 mm h?1 on five slopes. ERN for most sediments were above unity, indicating the common occurrence of nitrogen enrichment accompanied with soil erosion in Beijing mountain area. Soil texture was not the only factor that influenced N enrichment in this experiment since the ERN for the two fine-textured soils were not always lower. Soil properties such as soil structure might exert a more important influence in some circumstances. The selective erosion of clay particles was the main reason for N enrichment, as implied by the significant positive correlation between the ER of total nitrogen and clay fraction in eroded sediments. Significant regression equations between ERN and sediment yield were obtained for two pairs of soils, which were artificially categorized by soil texture. The one for fine-textured soils had greater intercept and more negative slope. Thus, the initially higher ERN would be lower than that for the other two soils with coarser texture once the sediment yield exceeded 629 kg ha?1. 相似文献
123.
甲酸、乙酸和草酸是降水中有机酸的主要成分。研究选用离子色谱法同时测定降水中的甲酸、乙酸和草酸,并对降水样品中3种有机酸的保存条件进行了研究。优化后的色谱条件为4. 0 mmol/L Na_2CO_3和1. 2 mmol/L NaHCO_3混合淋洗液,淋洗液流速为1. 0 m L/min,进样体积为200μL,电导池温度为30℃,柱温为室温。甲酸、乙酸和草酸的检出限分别为0. 002、0. 005、0. 005 mg/L,实际降水样品测定时平行样的相对标准偏差为1. 4%~12%,加标回收率为95%~118%。样品采集后需尽快用0. 45μm聚醚砜微孔滤膜过滤,4℃以下冷藏密封保存,2 d内测定。若用氢氧化钠溶液调节p H至8~10,样品可保存7 d。 相似文献
124.
ABSTRACTThe present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J0V0Y0, J1V0Y0, J0V1Y0, J0V0Y1, J1V1Y0, J1V0Y1, J0V1Y1, J1V1Y1. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J0 – no straw powder, J1 – 0.2 kg straw powder, Y0 – no manure, Y1 – 0.3 kg manure, V0 – no microbial fertilizer, V1 – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments. 相似文献
125.
126.
Yonglan Tian 《International Journal of Green Energy》2016,13(15):1556-1563
In the past decades, a novel strategy has arisen, as required by time, to get a rational production of biogas from contaminated biomass, which may be, on purpose, harvested from contaminated soil phytoremediation process. The present review focuses on the possibility and potential of utilizing the agricultural residues generated during phytoremediation for production of biogas. As a general result of the studies compiled in this review, the harvested biomass can subsequently be utilized for the winning of biogas, and it provides a solution of waste disposal for phytoremediation technology. According to the analysis of previous results, not more than 1 mg/L of cadmium in fermenters shows promoting or at least no inhibitory effect on cumulative biogas yields. This strategy is promising for dealing with both environmental and energy problems in spite of many challenges in the coming future. 相似文献
127.
为研究建筑废物红砖和工业废物煤渣用作人工湿地脱氮基质的可行性,分别通过静态吸附实验和动态NHf—N去除效果实验进行考察。结果表明,红砖和煤渣对NH4+-N最大静态吸附量分别为0.2533mg/g和0.0533mg/g,其吸附等温曲线均符合Freundlich型吸附方程,吸附常数分别为0.0419和0.0091;红砖煤渣组合对污水中NH4+-N平均动态脱除率达到41.18%,高于红砖的37.63%和煤渣的30.92%。 相似文献
128.
应用自主研制的强化循环厌氧反应器(SCAR)中试规模处理实际印染废水,研究反应器的启动特性。反应器接种厌氧颗粒污泥后启动运行83 d,形成连续内循环并实现了对印染废水处理的高效稳定运行。在进水COD浓度1 000~3 650 mg/L、系统容积负荷0.7~6.4 kg/(m3·d)条件下,废水COD和色度平均去除率分别达到55%和73%。反应器内较高浓度的NH+4-N保证了系统pH的稳定性,350~600 mg/L的NH+4-N浓度没有对强化循环厌氧反应器产生抑制作用,系统内也没有出现VFA(以乙酸计)积累。启动过程中,厌氧颗粒污泥的粒径增大、沉降性能变好。启动实验完成时,反应器内微生物的脱氢酶活性(以TF计)和辅酶F420浓度分别为3.4973 mg/(g·h)和0.1872μmol/g。 相似文献
129.
于2018年—2019年在鄱阳湖区周边选取4个县(区)10个村庄的典型门塘开展浮游藻类采样调查。研究共鉴定出藻类6门83种,以蓝藻门、绿藻门和硅藻门为主;浮游藻类细胞密度全年范围为7.30×104个/L~2.78×1011个/L,年均值为1.4×1010个/L,其中夏季细胞密度最大,冬季细胞密度最小;优势种主要有小环藻、微囊藻、铜绿微囊藻、卵形隐藻等,且具有较为明显的季节演替,全年优势种为小环藻;藻类多样性指数(H′)年均值为1.49,丰富度指数(M)年均值为1.92,全年水体生物学评价结果为中度污染。 相似文献
130.
工业内窥镜是电站锅炉内部检验中不可或缺的设备,主要用来对集箱、减温器、受热面管等内部人眼无法观察到的地方进行检验,从而确定承压部件内部是否存在严重影响锅炉安全运行的缺陷.本文通过对锅炉内窥实例进行分析和总结,阐述内窥镜检查在锅炉内检中的重要性并给相关工作人员提供借鉴与参考. 相似文献